|
| virtual auto | get (const couchbase::collection &coll, const std::string &id) -> std::pair< error, transaction_get_result >=0 |
| | Get a document from a collection.
|
| |
| virtual auto | get_replica_from_preferred_server_group (const couchbase::collection &coll, const std::string &id) -> std::pair< error, transaction_get_result >=0 |
| | Get a document copy from the selected server group.
|
| |
| template<typename Transcoder = codec::default_json_transcoder, typename Document , std::enable_if_t<!std::is_same_v< codec::encoded_value, Document >, bool > = true> |
| auto | insert (const couchbase::collection &coll, const std::string &id, const Document &content) -> std::pair< error, transaction_get_result > |
| | Insert a document into a collection.
|
| |
| template<typename Transcoder = codec::default_json_transcoder, typename Document , std::enable_if_t<!std::is_same_v< codec::encoded_value, Document >, bool > = true> |
| auto | replace (const transaction_get_result &doc, const Document &content) -> std::pair< error, transaction_get_result > |
| | Replace the contents of a document in a collection.
|
| |
| virtual auto | remove (const transaction_get_result &doc) -> error=0 |
| | Remove a document.
|
| |
| auto | query (const std::string &statement, const transaction_query_options &options={}) -> std::pair< error, transaction_query_result > |
| | Perform an unscoped query.
|
| |
| auto | query (const scope &scope, const std::string &statement, const transaction_query_options &opts={}) -> std::pair< error, transaction_query_result > |
| | Perform a scoped query.
|
| |
| virtual | ~attempt_context ()=default |
| |
The attempt_context is used for all synchronous transaction operations.
In the example below, we get a document then replace its content:
auto [tx_err, tx_res] = cluster.transactions()->run(
[=](std::shared_ptr<couchbase::transactions::attempt_context> ctx) ->
couchbase::error {
auto [err_ctx, doc] = ctx->get(collection, id_1);
if (err_ctx.ec()) {
fmt::print(stderr, "failed to get document \"{}\": {}\n", id_1, err_ctx.ec().message());
return {};
}
ctx->replace(doc, tao::json::value{ { "some", "other content" } });
return {};
});
if (tx_err.ec()) {
fmt::print(stderr,
"error in transaction {}, cause: {}\n",
tx_err.ec().message(),
tx_err.cause().has_value() ? tx_err.cause().value().ec().message() : "");
retval = 1;
} else {
fmt::print("transaction {} completed successfully\n", tx_res.transaction_id);
}
Get a document copy from the selected server group.
Fetch the document contents, in the form of a transaction_get_result. It might be either replica or active copy of the document. One of the use cases for this method is to save on network costs by deploying SDK in the same availability zone as corresponding server group of the nodes.
- Parameters
-
| coll | The collection which contains the document. |
| id | The unique id of the document. |
- Returns
- The result of the operation, which is an error and a transaction_get_result.
Select preferred server group in connection options:
cluster_options.network().preferred_server_group(selected_server_group);
Fetch document from the nodes that belong to selected server group only:
auto [tx_err, tx_res] = cluster.transactions()->run(
[=](std::shared_ptr<couchbase::transactions::attempt_context> ctx) ->
couchbase::error {
auto [err, doc] = ctx->get_replica_from_preferred_server_group(collection, id);
if (err) {
fmt::println(stderr, "failed to get document \"{}\": {}", id, err.ec().message());
return {};
}
fmt::println("document content: {}",
tao::json::to_string(doc.template content_as<tao::json::value>()));
return {};
});
if (tx_err.ec()) {
fmt::println(stderr,
"error in transaction {}, cause: {}",
tx_err.ec().message(),
tx_err.cause().has_value() ? tx_err.cause().value().ec().message() : "");
retval = 1;
} else {
fmt::println("transaction {} completed successfully", tx_res.transaction_id);
}
- See also
- network_options::preferred_server_group
-
https://docs.couchbase.com/server/current/manage/manage-groups/manage-groups.html
template<typename Transcoder = codec::default_json_transcoder, typename Document , std::enable_if_t<!std::is_same_v<
codec::encoded_value, Document >, bool > = true>
Replace the contents of a document in a collection.
Replaces the contents of an existing document. Note that currently this content can be either a std::vector<std::byte> or an object which can be serialized with the codec::tao_json_serializer.
- Template Parameters
-
| Content | Type of the contents of the document. |
- Parameters
-
| doc | Document whose content will be replaced. This is gotten from a call to attempt_context::get |
| content | New content of the document. |
- Returns
- The result of the operation, which is an error and a transaction_get_result.
The example below shows how to use custom transcoder with transactions.
The type should have transcoder to be defined. The only restriction is that the transcoder should mark encoded value with either codec::codec_flags::json_common_flags or codec::codec_flags::binary_common_flags. Behavior of transcoders with any other flags is not defined.
auto [err_ctx, doc] = ctx->get(collection, "the_ledger");
if (err_ctx.ec()) {
fmt::print(stderr, "Failed to retrieve \"the_ledger\": {}\n", err_ctx.ec().message());
return {};
}
auto the_ledger = doc.content_as<ledger, csv_transcoder>();
the_ledger.add_record("2024-09-01", "Cash", "Expenses", 1000, "Rent payment");
ctx->replace<csv_transcoder, ledger>(doc, the_ledger);
- See also
- transactions::transaction_get_result for more complete example
1.12.0